1. Field of the Invention
The present invention relates to a new and improved rotary type washer/extractor for textiles and other materials including a new and unique dynamic force minimizing, suspension system for supporting a rotating drum from a base or stationary structure of the machine. The new and improved dynamic suspension system of the present invention is also useful for devices other than rotary type washer/extractors in centrifugal machines of a wide variety wherein it is necessary and desirable to minimize loads or forces generated by a spinning mass which changes in terms of eccentricity, velocity and acceleration values during an operating cycle of the machine.
2. Background of the Prior Art
Rotary type centrifugal washing and extracting machines have been used in industrial and commercial laundry facilities and these machines generally employ large rotating drums for containing a mass of laundry material and washing liquid. After washing is completed, the wash liquid is centrifuged out of the rotating drum at a relatively high speed at the end of a washing phase.
The following U.S. patents disclose various prior art washing and extracting machines: Adachi et al., U.S. Pat. No. 4,970,645; Broadbent, U.S. Pat. No. 4,916,768; Fesmire et al., U.S. Pat. No. 4,479,371; Fesmire et al., U.S. Pat. No. 4,467,530 and Toth, U.S. Pat. No. 3,945,921.
A common problem assoc with all types of washer/extractors and other rotary centrifuge machines is the imbalance of material inside the machine. This imbalance generates unbalanced forces that occur during a spin cycle. The magnitude of the unbalanced forces often becomes more acute during high speed extraction phases than during relatively lower speed washing phases. In large industrial and commercial machines, the unbalanced forces cause noise and vibrations which are transmitted to floor and other supports even though force dampening type suspension systems are provided. Excessive forces are sometimes carried through the base or frame structure of a spinning washer/extractor and impact upon a floor or other structure of the building in which a machine is housed.
Attention has been addressed to reducing the magnitude of unbalanced forces transmitted through the base of such machines to underlying building supporting structures. The present invention is addressed towards a suspension system for such machines and designed for a minimization of such unbalanced forces so that a wider variety of locations for such machines are available with a minimum amount of floor structure or structural foundation base being required in the enclosed surrounding area.
U.S. Pat. No. 4,970,645 discloses a suspension control method and apparatus for a vehicle having each wheel of the vehicle independently supported on an air spring in conjunction with a controllable force damping shock absorber utilized for minimizing vibration and unbalanced forces. The disclosed suspension system provides a system for sampling the damper stroke position on the shock absorber at each wheel and generating a control signal to a central processing unit. The central processing unit sends an output signal to each wheel to adjust the air spring to provide a hard or soft ride and to adjust the shock absorber to provide a hard, middle or soft value of dampening.